DNS

How to Manage Users and Groups with useradd, groupadd and passwd on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Manage Users and Groups with useradd, groupadd and passwd on RHEL 9

While the earlier tutorial in this series covered the core useradd, usermod, and userdel tools for user lifecycle management, this guide goes deeper into the full toolkit for managing users and groups at scale on RHEL 9: bulk creation, password management with chpasswd, group administration with gpasswd, per-user resource limits with ulimit and /etc/security/limits.conf, user […]

Read more
Initial Server Setup with RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

Initial Server Setup with RHEL 9

Red Hat Enterprise Linux 9 (RHEL 9, codenamed “Plow”) is the most significant release of RHEL in years, built on Linux kernel 5.14, OpenSSL 3.0, and shipped with a hardened-by-default security posture including SELinux enforcing mode, nftables as the default firewall backend, and full support for the latest POWER, ARM, and x86_64 architectures. Whether you […]

Read more
How to Configure the Firewall on RHEL 9 with firewalld — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure the Firewall on RHEL 9 with firewalld

Red Hat Enterprise Linux 9 uses firewalld as its default firewall management daemon, backed by nftables as the kernel netfilter framework (replacing iptables which was the default in RHEL 7 and earlier). firewalld provides a zone-based model where each network interface is assigned to a trust zone — public, internal, dmz, trusted, and more — […]

Read more
How to Set a Hostname and FQDN on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Set a Hostname and FQDN on RHEL 9

A server’s hostname is its identity on the network. The fully qualified domain name (FQDN) combines the short hostname with the DNS domain, forming an address like web01.example.com. Many services depend on a correctly configured hostname and FQDN to function properly: email servers use the FQDN in SMTP HELO greetings (incorrect values cause delivery rejections), […]

Read more
How to Sync Time with Chrony on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Sync Time with Chrony on RHEL 9

Accurate time synchronization is not optional on a server — it is a hard requirement. TLS certificate validation fails when the clock is wrong by more than a few minutes. Kerberos authentication rejects tickets with a clock skew over 5 minutes. Cron jobs fire at the wrong time. Log correlation across multiple servers becomes impossible […]

Read more
How to Use tmux for Terminal Multiplexing on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Use tmux for Terminal Multiplexing on RHEL 9

Terminal multiplexing solves one of the most common problems in server administration: when your SSH connection drops mid-task, any running process in that session is killed. With tmux, your terminal sessions run inside a server-side process that persists independently of your SSH connection. You can detach from a session, disconnect, reconnect hours later from a […]

Read more
How to Configure Log Rotation with logrotate on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Log Rotation with logrotate on RHEL 9

Log files are the primary diagnostic tool for server administrators — but without rotation they become a problem in their own right. An unrotated /var/log/nginx/access.log on a busy server can grow to tens of gigabytes within weeks, filling the filesystem, crashing the logging application, and making the log itself unusable because no tool can efficiently […]

Read more
CHAT